One speech that analysts will talk about as a turning point if Barack Obama prevails is Bill Clinton’s Wednesday night nominating address, which demonstrated yet again that Clinton is a political nonpareil, a communicator the likes of which we haven’t seen since Ronald Reagan.

Clinton highlighted all that Obama has accomplished. And he counseled patience on the incumbent’s behalf by noting that the economic problems confronting this president were much worse than those he himself had faced.

But for my money, the greatest clarity, and thus the greatest value, came in his critique of the Republicans both in Congress and on the GOP ticket.

He placed the blame for governmental gridlock where it mostly belongs: In the lap of congressional Republicans and particularly that of Senate Minority Leader Mitch McConnell, who has made filibuster-based obstructionism his regular tactic in the hope that voters frustrated by inaction will vote the president out. To date, McConnell has largely gotten away with that, which is why there should be much more focus on his actions.

The former president also reasserted reality in a campaign where GOP plans flout fiscal gravity and GOP accusations often fail the truth test. He drove home a crucial fiscal point, one independent experts have also made: Given today’s budgetary situation, it’s impossible for Mitt Romney and Paul Ryan to preserve the Bush tax cuts and offer another $5 trillion round of rate reductions while also attacking the deficit.

Clinton is a political nonpareil, a communicator the likes of which we haven’t seen since Ronald Reagan.

Clinton exposed that flight of fiscal fancy by noting that the Republican answer when queried about how they will pay for their tax cuts is: “See me after the election on that.”

And yet, he didn’t resort to the oft-repeated Democratic assertion that Republicans will raise middle class taxes. His was a more nuanced assessment: If Romney and Ryan do indeed pay for their tax cuts by eliminating loopholes and deductions, the base-broadening would be so extensive that it would have to result in higher middle-class taxes. To avoid that reality while still offsetting their tax cuts would require even deeper reductions in vital domestic programs, he noted. The only other course, Clinton said, would be to simply let the new tax cuts explode the debt.

Those are indeed the basic choices — and as the last president to preside over a balanced budget, Clinton speaks with real authority on the issue.

His other big oratorical achievement was sending a truth torpedo churning toward the hull of a Republican campaign based more on distortions than true differences.

Two Republican assertions in particular have stuck with voters. One is the completely fictitious charge that the Obama administration has eliminated the work requirement for welfare. As fact checker after fact checker has pointed out, that’s simply not true; Clinton, the president who signed welfare reform, made that point in no uncertain terms.

The second charge is that Obama has raided Medicare in a way that will hurt beneficiaries by reducing payments for providers and insurance companies. Clinton’s explanation of why that’s not the case was clear and persuasive — and became more so when he pointed out that Ryan, the House budget chief, had included precisely the same savings in his own fiscal plans.

“It takes some brass to attack a guy for doing what you did,” he said, marveling in wry astonishment at Ryan’s mendacity.

Yes it does. Ryan’s response, of course, is that Romney would restore those dollars, and it’s the ticket-topper’s position that counts, not his. But it’s also true that Obama uses that money to help close the prescription-drug doughnut hole, whereas by repealing the health care law, Romney would reopen that gap in prescription drug coverage.

It’s an exaggeration to suggest, as some have, that Clinton’s speech is enough to carry the day for Obama. But the former president certainly helped dispel the political fog — and by so doing, he has aided Obama greatly.